Laminar air flow workstation with temperature control

ABSTRACT

Laminar air flow workstation, comprising: a working chamber (1) comprising a work table (2), an air circulation system (3) comprising first heating means (4), and configured to circulate heated air in the workstation and direct a heated and temperature controlled air flow towards the work table (2), wherein the working chamber comprises a front handling opening (6) in fluid connection with the surroundings (7), and configured such that the work table (2) can be accessed from the surroundings (7). Also disclosed are the use of the workstation for handling and/or microscopy of biological materials, such as tissue, embryos, and stem cells, as well as the use of the workstation for microbiological safety workstation in accordance with ISO/EN 12469.

FIELD OF INVENTION

The present invention relates to a laminar air flow workstation, and theuse of the workstation for handling and/or microscopy of biologicalmaterials, such as tissue, embryos, and stem cells, as well as the useof the workstation for microbiological safety workstation in accordancewith ISO/EN 12469.

BACKGROUND OF INVENTION

Laminar air flow workstations, also denoted benches or cabinets, areused for safely working with materials that may be contaminated, such ascontaminated with pathogens, or for handling materials that must beprotected from exposure to the surroundings. For example when examiningbiological material, such as tissue, embryos, and stem cells, exposureto the surrounding atmospheric environment and the surroundingtemperature may be detrimental.

Depending on the level of personnel and environmental protectionprovided by the workstation, and the level of product protectionprovided by the workstation, different classes of workstations aredefined. Laminar flow cabinets only provide product protection, whereasclass II cabinets provide both product and personnel protection. ClassII workstations may be further certified to various ISO standards, suchas ISO 12469.

Conventional laminar air flow workstations operate by blowing a verticallaminar air flow of sterile and/or filtered air, over the samples thatare being handled.

To enable temperature control of the samples to be handled, the samplesmay be placed on heating means such as a heat plate to maintain adesired temperature. In addition, or alternatively, the workstation mayform a closed system with no direct access from the surrounding, and theair flow may be heated, whereby the temperature of the sample surfacecan be controlled precisely.

Large volumes of aft are used in closed workstations with heated airflow. Thus, during operation, the workstations are noisy due to the fansand pumps driving the large volumes, and the energy consumption of theworkstation, and the heat loss to the surroundings, are significant. Toremedy this, the air may be partially recycled. However, the efficiencyand simplicity is significantly reduced for a closed workstation, as thesample handling within the workstation as well as the transfer ofsamples to and from the workstation, is complicated.

It is therefore desirable to provide a laminar air flow workstationwhich is easily accessible from the surroundings, but with reducedenergy consumption and heat loss to the surroundings, and a preciselytemperature controlled air flow.

SUMMARY OF INVENTION

It is a purpose of the present invention to provide a laminar air flowworkstation and class II workstation, preferably with a level of ISO12469 approval. It is furthermore an purpose of the invention to providea workstation that is easily accessible from the surroundings, hasimproved temperature control, and where the workstation in operation hasa reduced noise level.

In a first aspect, the present invention provides a laminar air flowworkstation, comprising:

a working chamber 1 comprising a work table 2,

an air circulation system 3 comprising first heating means 4, andconfigured to circulate heated air in the workstation and direct aheated and temperature controlled air flow towards the work table 2,

wherein the working chamber comprises a front handling opening 6 influid connection with the surroundings 7, and configured such that thework table 2 can be accessed from the surroundings 7.

In a second aspect, the workstation according to the first aspect isused for handling and/or microscopy of biological materials, such astissue, embryos and stem cells, and/or used for a microbiological safetyworkstation in accordance with ISO/EN 12469.

DESCRIPTION OF DRAWINGS

The invention will in the following be described in greater detail withreference to the accompanying drawings.

FIG. 1: shows an embodiment of a laminar air flow workstation accordingto the present invention.

FIG. 2: shows an embodiment of a laminar air flow workstation accordingto the present invention, where the workstation further comprises aninsulation layer 18 on the outer surfaces, an inlet filter 20 a, and anoutlet filter 19 a.

FIG. 3: shows an embodiment of a laminar air flow workstation accordingto the present invention, where the workstation is configured foroptical microscopy, suitable for inspection of biological materials,such as living cells,

FIG. 4: shows an embodiment of a laminar air flow workstation accordingto the present invention, where air is drawn from the surroundings 7into the workstation at the front handling opening 6.

FIG. 5: shows a top view of an embodiment of a work table for a laminarair flow workstation according to the present invention,

FIG. 6: shows a top view of an embodiment of a work table for a laminarair flow workstation according to the present invention, where the worktable comprises second heating means 14, and where the position of theheating means are indicated.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an embodiment of a laminar air flow workstation, alsodenoted LAF (Laminar Air Flow) cabinet. LAFs are in general used forlaboratory work on materials, or samples that are temperature sensible,and/or require a clean environment, and which furthermore may constitutea health risk to human beings. Examples of such materials includebiological materials, such as tissue, embryos and stem cells.

The workstation comprises a working chamber 1, a work table 2, and afront handling opening 6. The front handling opening opens towards thesurroundings 7, and the size of the opening can be varied by slidingmeans configured such that a transparent front 6 a can be displaced inan upward or downward direction.

The person(s) working at the workstation will be placed in front of theworkstation, and can work with his/hers hands inside the workingchamber, such as manipulate samples or operate instruments e.g. amicroscope, as the working chamber and work table are visible throughthe transparent front 6 a. Depending on the length of the workstation,one or more persons can work next to each other. Preferably, aworkstation with a length of 122 cm (4 foot) is suitable for one person,and a workstation with a length of 183 cm (6 foot) is suitable for twopersons.

It is advantageous that the samples and instruments to be handled can beplaced in a stable position on the work table 2.

Thus, in an embodiment of the invention, the work table 2 issubstantially horizontal.

Temperature Control of Sample

In FIG. 1, the temperature of the items placed on the work table 2 iscontrolled by directing a heated and temperature controlled air flowtowards the work table, as shown by the arrows inside the workingchamber 1.

For precise temperature control and minimal air resistance in thesystem, it is advantageous that the heated air flow is essentiallylaminar and/or perpendicular to the work table.

In an embodiment of the invention, the workstation is configured suchthat the direction of the air flow towards the work table 2 isessentially laminar and/or perpendicular to the work table.

When examining biological samples it advantageous that the temperatureof the heated air flow is similar to the natural temperature of thebiological sample.

Thus, in a further embodiment of the invention, the air flow directedtowards the work table 2 is heated and configured to be controlled to beabove 25° C., more preferably above 30° C., such as essentially 37° C.

The temperature of the items placed on the work table 2 may additionallybe controlled by use of heating means 14 placed within or embedded inthe work table 2, and/or placed on top of the work table 2. The heatingmeans enable the work table to be partly heated, and configured to betemperature controlled, whereby the temperature of the items placed onthe work table is controlled.

In a further embodiment of the invention, the work table 2 comprisessecond heating means 14, such that the work table is heated andconfigured to be temperature controlled.

When the heating means are embedded within the work table, thetemperature controlled area of the work table surface will depend on thethermal conductivity properties of the work table material. The thermalconductivity of the material should be sufficient to transfer thethermal energy from the heating means to the surface of the work table,and to obtain a uniform temperature on an area of the surface of thework table.

In a further embodiment of the invention, the work table 2 comprises amaterial with thermal conductivity properties, such as a metal, analloy, a composite, or any combinations thereof,

FIG. 6 shows a top view of an embodiment of a work table, where theposition of the heating means 14 are indicated by dashed lines. Thus,the dashed lines indicate the in-plane area of the heating means. Withinat least the indicated surface area of the work table, the temperatureof the work table surface is uniform, and can be controlled to be e.g.37° C.

In a further embodiment of the invention, the in-plane area of thesecond heating means (14) constitute at least 25%, more preferably atleast 35%, and most preferably at least 40 or 50% of the upper surfacearea of the work table 2.

Microscopy

The samples to be handled within the workstation may be examined bymicroscopy, FIG. 3 shows an embodiment of a laminar air flowworkstation, where the workstation comprises a microscope 15, and wherethe workstation is configured for carrying out microscopy.

In FIG. 3, the sample 15 c to be examined by microscopy is placed on thework table 2, and the microscope lens 15 b positioned above the sample.The sample object 15 c is observed through the ocular 15 a, which may beaccessible from the surroundings, such as at the outer surface of thetransparent front 6 a.

The workstation may further be configured for optical transmissionmicroscopy, where a beam of light is transmitted through the sample tobe examined. FIG. 3 shows an embodiment of a workstation configured fortransmission microscopy. The work table 2 comprises a transparent part17, on top of which the sample 15 c is placed. The sample 15 c istransmitted by light from the light source 16 placed below thetransparent part of the work table. To further ensure temperaturecontrol of the transmitted sample 15 c, the sample may be placed on atransparent heated part 17 a of the work table, such as heated glass.

In an embodiment of the invention, the workstation comprises amicroscope 15, such as an optical microscope, and/or a light source 16.In a further embodiment, the workstation further comprises a transparentfront 6 a configured for microscopic inspection.

In a further embodiment of the invention, the work table 2 comprises atransparent part 17, and the light source 16 is optionally placedsubjacent to the transparent part. In a further embodiment, thetransparent part 17 comprises a transparent part configured to be heated17 a, such as a part made of glass. In a further embodiment, at least apart of the transparent part is heated and configured to be temperaturecontrolled.

Air Circulation System

The air in the workstation is heated and circulated within theworkstation by the air circulation system 3. Thus, all parts of the aircirculation system are in fluid connection with each other. Embodimentsof air circulation systems are shown in FIGS. 1-4.

In the embodiments of FIGS. 1-3, air from the surroundings 7 is drawninto the air circulation system 3 at an air inlet 20. The entered air isthen heated by being brought into contact with the first heating means4. The first heating means 4 are configured to be temperaturecontrolled, whereby the temperature of the entered and heated air can becontrolled. Subsequently, the heated and temperature controlled airenters the working chamber 1, and is directed towards the work table 2.The table 2 comprises one or more ducts 5, and/or the working chambercomprises a rear duct 8, and the air flow directed towards the worktable 2 is drawn through the duct(s). The air drawn through the duct(s)is subsequently either recycled, i.e. passed by the first heating means4 and re-entered into the working chamber 1, or released to thesurroundings 7 by an air outlet 19, or a combination thereof.

For continuous operation of the workstation, the amount of air releasedto the surroundings, is replaced by air from the surroundings enteringat the air inlet 20.

An alternative embodiment of the air circulation system 3 is shown inFIG. 4. In this embodiment, the air is drawn from the surroundings 7into the workstation at the front handling opening 6. The entered air issubsequently drawn through the duct(s) 5 of the work table 2, andbrought into contact with the first heating means 4 and circulated tothe working chamber 1 in similarly manner as in FIGS. 1-3.

In an embodiment of the invention, the front handling opening 6comprises the air inlet 20.

The air circulation system 3, and implicitly the air entering/exitingthe air circulation system, may be operated by use of an air flowgenerator 11. In an embodiment of the invention, the air circulationsystem 3 comprises an air flow generator 11, such as a fan. In a furtherembodiment, the air flow generator 11 is configured to control the airflows within the air circulation system 3.

To minimize the amounts of contaminants entering the air circulationsystem 3 at the air inlet 20, and exiting the air circulation system 3at the air outlet 19, the inlet and/or outlet may comprise filteringmeans as illustrated in FIGS. 2-4.

In an embodiment of the invention, the workstation comprises an airinlet 20, and an air outlet 19, wherein the air inlet optionallycomprises an inlet filter 20 a, and the air outlet optionally comprisesan outlet filter 19 a.

The air circulation system 3 may further be operated by use of an airflow generator 11 in combination with a pressure chamber 13, or pressurebox, where the pressure box is a part of the air circulation system withoverpressure, or positive pressure. Optionally, the first heating means4 are placed inside the pressure chamber as illustrated in FIGS. 1-4.

In an embodiment of the invention, the air circulation system 3 furthercomprises a pressure chamber 13, which in combination with the air flowgenerator 11 is configured to control the air flows within the aircirculation system 3.

Energy Consumption

To minimize the energy consumption of the workstation, and the size ofthe air flows passing from the workstation to and from the surroundings,it is advantageous that part of the air circulated in the workstation isrecycled.

In an embodiment of the invention, the air circulation system 3 isconfigured to recycle at least a part of the circulated air. In afurther embodiment, at least 70%, more preferably at least 80%, and mostpreferably at least 90% of the circulated air is recycled. In a furtherembodiment, the amount of recycled air is controlled by flow controlmeans, such as valves, slides, or throttles.

To further minimize the heat loss from the workstation and to thesurroundings, all or some of the outer surfaces of the workstation maybe completely or partly covered by an insulating material 18. FIGS. 2and 4 show embodiments of workstations comprising an insulating layer 18on the outer surfaces.

In an embodiment of the invention, the workstation further comprises aninsulation layer 18 on one or more outer surface(s).

The energy consumption and heat loss may be further reduced by the useof heat exchanging means 12, whereby air entering at the inlet 20 fromthe surroundings 7, are partly heated by the air released from theworkstation and to the surroundings 7. Embodiments of workstationscomprising heat exchanging means 12 are illustrated in FIGS. 1-4.

By use of a cross heat exchanger as heat exchanging means 12, it wasseen possible to heat the air entering at the inlet 20 with up to 10° C.For example, air entering at the inlet 20 with a temperaturecorresponding to the surroundings of 22° C., was heated to 29° C., whilethe air released from the workstation decreased in temperature from 37°C. to 30° C.

In an embodiment of the invention, the air circulation system furthercomprises heat exchanging means 12. In a further embodiment, the heatexchanging means 12 are selected from the group consisting of: heatexchanger, heat pump, and any combinations thereof. In a preferredembodiment, the heat exchanging means 12 is a cross heat exchanger.

In a further embodiment of the invention, the heat exchanging means 12are configured to exchange air between the air circulation system 3 andair with essentially the same temperature as the surroundings 7.

Depending on the configuration of the air circulation system 3, the heatexchanging means 12 may be placed differently in the workstation. Forthe configuration embodied in FIGS. 1-3, where the air enters theworkstation at the separate inlet 20, the heat exchanging means 12 areplaced in the vicinity of the inlet 20, or on the top of theworkstation.

In this embodiment of the invention, the heat exchanging means areconfigured to exchange heat between air flowing from the inlet 20 to theair flow generator 11, and air flowing from the pressure chamber 13 tothe outlet 19.

For the configuration of the air circulation system 3 embodied in FIG.4, where the air enters the workstation at the front handling opening6,20, the heat exchanging means 12 are placed in the vicinity of therear of the workstation, or at a distance from the inlet 20.

Thus, in another embodiment of the invention, the heat exchanging meansare configured to exchange heat between air flowing from the pressurechamber 13 to the outlet 19, and air flowing from the part of the aircirculation system placed below the worktable 2 to the air flowgenerator 11.

Work Table

By the term “work table” as used herein is meant a three-dimensionalrectangle, or a box-shaped or hyper rectangular, component. The worktable comprises an upper surface, where the work is carried out by auser, and the lower surface, which is the surface on the opposite sideof the box. The other surfaces of the box comprise the edges of the worktable. The work table front is the part of the work table in thevicinity of the front handling opening, and the work table rear is atthe opposite edge, i.e. the part of the work table in the rear of theworkstation.

By the term “in-plane” is meant an orientation parallel to the uppersurface, and by the term “cross-plane” is meant an orientationperpendicular to the upper surface, and e.g., parallel to one of theedges.

FIG. 5 shows an embodiment of a work table seen from a top view, showingthe work table upper surface. The work table is seen to comprise alarger rear duct 8, and a multiple of smaller ducts 5 which are orientedcross-plane of the work table, and placed along the front edge, andpartly the two side edges, of the work table.

The air flow resistance, and therefore also the noise, of theworkstation is dependent on the duct(s) of the work table 5 and theduct(s) of the workstation 8. To minimize the energy consumption of theworkstation, it is advantageous that the duct(s) are configured tominimize the air flow resistance within the air circulation system 3.

In an embodiment of the invention, the work table 2 further comprisesone or more ducts 5, such that at least part of the air flow directedtowards the work table can be drawn through the duct(s).

In a further embodiment, the one or more ducts 5 extend from an uppersurface of the work table, and to a lower surface of the work table,and/or to an edge surface of the work table. In a further embodiment,the one or more ducts 5 are oriented cross-plane of the work table. In afurther embodiment, the one or more ducts 5 are positioned adjacent toone or more edge(s) of the work table.

In a further embodiment of the invention, the geometry of the one ormore ducts 5 are selected from the group consisting of: cylindrical,columnar, polygonal columnar, such as hexagonal columnar, and anycombinations thereof.

In a further embodiment of the invention, the in-plane area of the oneor more ducts 5 constitute at least 5%, more preferably at least 10% or20%, and most preferably at least 25% of the upper surface area of thework table 2.

To further minimize the air flow resistance of the air circulationsystem, the working chamber may in addition to the duct(s) of the worktable 2, comprise one or more rear duct(s) 8. The rear duct(s) may beplaced in the rear of the working chamber 1, such as comprised withinthe work table 2 in the rear part of the work table as illustrated inFIG. 5.

In an embodiment of the invention, the working chamber comprises one ormore rear duct(s) 8 such that at least a part of the air flow directedtowards the work table 2 can be drawn through the rear duct(s).

The energy consumption of the workstation may further be improved if themajority of the circulated air is drawn through the rear duct(s) 8,compared to the duct(s) 5 comprised in the work table.

This is particularly the case for the embodiments shown in FIGS. 1-3,where the risk of air entering from the surroundings 7 and into theworking chamber 1 via the front handling opening 6, is reduced.

In an embodiment of the invention, the air flow drawn through the rearduct(s) 8 is larger than the air flow drawn through the one or moreducts (5).

Working Chamber

In the embodiments shown in FIGS. 1-4, the heated and temperaturecontrolled air enters the working chamber 1, from the pressure chamber13, through an opening 9, and is directed towards the work table 2.

To avoid contaminants entering the working chamber 1, filtering means 10may be used such that the heated and temperature controlled air isfiltered before entering the working chamber 1. The filter may forexample be a High-Efficiency Particulate Arrestance (HEPA), whereparticles above a certain size are removed.

In an embodiment of the invention, the workstation further comprises afilter 10, such as a HEPA filter, or a filtered opening 9.

The filter 10 may further be positioned above the work table, andconfigured to affect the distribution of the air flow directed towardsthe work table 2.

In an embodiment of the invention, the filter 10 is positioned such thatfiltered air is directed into the working chamber 1. In anotherembodiment, the workstation comprises a filtered opening 9 in the aircirculation system 3 located above the work table 2. In a furtherembodiment, the filtered opening 9 is configured to evenly distributethe heated air vertically downwardly within the working chamber 1 andtowards the work table 2.

In some embodiments of the invention, such as the embodiments shown inFIGS. 1-3, it is advantageous that the amount of air entering from thesurroundings 7 and into the working chamber 1 via the front handlingopening 6, is minimized. The amount of air entering through the fronthandling opening 6 is determined by the pressure difference between theworking chamber 1 and the surroundings 7. The pressure of the workingchamber 1 is further determined by the ratio of air flowing into theworking chamber through the filtered opening 9, and air drawn throughthe duct(s) 5,8.

Thus, in preferred embodiments, the air pressure in the working chamber1 is essentially similar or slightly lower than the air pressure of thesurroundings 7. More preferably, the pressure difference across thefront handling opening 6 is zero, and no air enters the working chamberthrough the front handling opening.

In an embodiment of the invention, the air circulation system 3 isconfigured such that the pressure difference across the front handlingopening 6, i.e. between the working chamber 1 and the surroundings 7, isessentially zero.

In a further embodiment, the workstation is configured such that the airflow through the filtered opening 9 is essentially similar or lower thanthe air flow drawn through the duct(s) 5,8, more preferably essentiallysimilar.

In some embodiments of the invention, such as the embodiment shown inFIG. 4, the handling opening 6 is used as air inlet 20. For this tooccur, there must be a significant pressure difference across the fronthandling opening 6, and the pressure in the working chamber 1 must belower compared to the surroundings 7.

In an embodiment of the invention, the workstation is configured suchthat the pressure is significantly lower in the working chamber 1compared to the surroundings 7.

REFERENCE NUMBERS

-   1—working chamber-   2—work table-   3—air circulation system-   4—first heating means-   5—ducts-   6—front handling opening-   6 a—transparent front-   7—surroundings-   8—rear duct-   9—filtered opening-   10—filter-   11—air flow generator-   12—heat exchanging means-   13—pressure chamber-   14—second heating means-   15—microscope-   15 a—occular-   15 b—lense-   15 c—sample-   16—light source-   17—transparent part of work table-   17 a—transparent heated part of work table-   18—insulation layer-   19—air outlet-   19 a—outlet filter-   20—air inlet-   20 a—inlet filter

The invention claimed is:
 1. A laminar air flow workstation, comprising:a working chamber comprising a work table and a front handling opening,the front handling opening being in fluid communication with asurrounding environment and configured such that the work table isaccessible from the surrounding environment; a filter positioned tofilter air directed into the working chamber; and an air circulationsystem configured to circulate the air in the laminar air flowworkstation and to direct a flow of the air towards the work table, theair circulation system comprising: an air flow generator configured tocontrol the flow of the air, a pressure chamber disposed above the worktable, and a heating means disposed within the pressure chamber andpositioned downstream of and laterally to the air flow generator,wherein the heating means is spaced apart from the filter, positioneddirectly above the filter, and positioned upstream of the filter to heatthe air after the air flows from the air flow generator and before theair contacts the filter and passes into the working chamber, such thatthe heating means, the air flow generator, and the pressure chambertogether provide an operational configuration that heats and controls atemperature of the air.
 2. The laminar air flow workstation according toclaim 1, wherein the air in the flow directed towards the work table isheated and controlled to be above 25° C.
 3. The laminar air flowworkstation according to claim 1, wherein the flow of the air directedtowards the work table is essentially laminar and/or is directedperpendicularly to the work table.
 4. The laminar air flow workstationaccording to claim 1, wherein the heating means comprises a firstheating means, and wherein the work table comprises a second heatingmeans for heating and controlling a temperature of the work table. 5.The laminar air flow workstation according to claim 1, wherein the worktable comprises a thermally conductive material.
 6. The laminar air flowworkstation according to claim 1, further comprising a microscope. 7.The laminar air flow workstation according to claim 6, furthercomprising a transparent front portion configured to permit inspectionof the microscope, and wherein the work table comprises a transparentpart disposed above a light source associated with the microscope. 8.The laminar air flow workstation according to claim 1, wherein the worktable comprises one or more ducts through which at least part of theflow of the air directed towards the work table can be drawn.
 9. Thelaminar air flow workstation according to claim 1, wherein the workingchamber further comprises one or more rear ducts through which at leasta part of the flow of the air directed towards the work table can bedrawn.
 10. The laminar air flow workstation according to claim 1,further comprising a filtered opening disposed in the air circulationsystem and above the work table and configured to evenly distribute theflow of the air vertically downward within the working chamber andtowards the work table.
 11. The laminar air flow workstation accordingto claim 1, wherein the air flow generator is further configured tocontrol an air inflow and an air outflow at the air circulation system.12. The laminar air flow workstation according to claim 11, wherein theair circulation system further comprises a heat exchanging meansselected from a group comprising a heat exchanger, a heat pump, and anycombinations thereof.
 13. The laminar air flow workstation according toclaim 12, wherein the heat exchanging means comprises a cross heatexchanger.
 14. The laminar air flow workstation according to claim 12,wherein the pressure chamber, in combination with the air flowgenerator, is configured to further control the air inflow and the airoutflow at the air circulation system.
 15. The laminar air flowworkstation according to claim 14, further comprising an air inletcomprising an inlet filter and an air outlet comprising an outletfilter.
 16. The laminar air flow workstation according to claim 15,wherein the heat exchanging means is configured to exchange air betweenthe air circulation system and air with essentially the same temperatureas the surrounding environment.
 17. The laminar air flow workstationaccording to claim 1, wherein the air circulation system is configuredto recycle at least a part of the air that has been heated by theheating means.
 18. The laminar air flow workstation according to claim1, wherein the air circulation system is configured such that a pressuredifference between an interior region of the working chamber and thesurrounding environment, across the front handling opening, isessentially zero.
 19. The laminar air flow workstation according toclaim 1, wherein the laminar air flow workstation is configured suchthat a pressure is significantly lower in the laminar air flowworkstation compared to a pressure of the surrounding environment.